6 foods to avoid while taking MiraLax

In this article:

• How MiraLax works
• Foods to avoid
• Foods to prioritize
• Gastrointestinal side effects
• Maximizing MiraLax benefits

In this article

• How MiraLax works
• Foods to avoid
• Foods to prioritize
• Gastrointestinal side effects
• Maximizing MiraLax benefits

MiraLax is a popular brand-name, over-the-counter (OTC) laxative that helps relieve constipation. Containing the active ingredient polyethylene glycol 3350 (PEG 3350), MiraLax is FDA approved to treat occasional constipation in adults. It has several off-label uses, too, including treating chronic constipation, constipation related to irritable bowel syndrome (IBS), bowel preparation for colonoscopy procedures, and treating constipation in children (which the American Academy of Pediatrics considers safe).

For most people, MiraLax is an effective way to relieve constipation without any side effects or health risks. You can take it with many different foods and drinks as part of a normal diet, but if you’re hoping to poop as quickly as possible, there are some foods you should avoid. 

Saturated fat, ultra-processed foods, alcohol, and unripe bananas, for example, have been shown in studies to increase the risk of constipation. Eating these foods while taking MiraLax could make it harder for the medication to treat your symptoms. Here’s what to know about what you should and shouldn’t eat on MiraLax.

How MiraLax works

MiraLax is an osmotic laxative, says Alyssa Simpson, RDN, CGN, CLT, a digestive health dietitian in Phoenix, Arizona. This means it works by increasing the amount of water in your intestines to make your stool softer and easier to pass. It’s considered a gentle, predictable laxative. Unlike stimulant laxatives such as Dulcolax (bisacodyl), “it doesn’t rely on stimulating your gut muscles, so it tends to cause fewer side effects, giving your gut a little nudge, [not] a harsh push,” Simpson says.  

Most people who take MiraLax will have a bowel movement in one to three days, according to the manufacturer. 

6 foods to avoid with MiraLax

MiraLax isn’t directly affected by anything you eat. Simpson says it doesn’t need to be absorbed in your intestines to work, so it doesn’t interact with foods or drinks. However, eating foods that cause constipation can make it harder for MiraLax to do its job. It’s like trying to unclog a toilet while flushing down reams of toilet paper. 

To help MiraLax work effectively in your intestines, it’s best to avoid the following constipation-causing foods while taking it.  

1. Foods high in saturated fat

Foods with a high saturated fat content are known for slowing down your digestive system and causing constipation. Common dietary sources of saturated fat include:

• Red meat
• Fried foods
• Butter
• Coconut and palm oil
• Whole-fat dairy products 

One study found that a diet high in saturated fat was associated with participants having fewer than three stools per week. In this study, the constipation risk was even higher for people older than 65 with diabetes and people with uncontrolled diabetes. Other types of fat are not as closely related to constipation as saturated fat. Another study, for example, points out that polyunsaturated fats like omega-3s help your intestines maintain a healthy balance of bacteria, reducing the risk of constipation.  

2. Dairy

Full-fat dairy contains saturated fat, a common trigger for constipation. Dairy doesn’t increase constipation in everyone, per a recent study, but some people find that eating large amounts of dairy products like milk, cheese, and yogurt makes it harder for them to have regular bowel movements. 

On top of that, some people may also be lactose intolerant, or unable to fully break down the sugar in milk (lactose), without realizing it. One study suggests that about 30% of people with lactose intolerance have constipation instead of the more common symptoms of abdominal pain, bloating, diarrhea, and gas.

3. Ultra-processed foods

A food is considered processed when it’s somehow changed or transformed from its natural state. Much of the food we eat is processed in some way. Vegetables are cleaned or frozen; oats are milled; meat is ground into patties. But when food is significantly changed from its natural state, it’s called ultra-processed. For example, pepperoni, instant noodles, soda, potato chips, cookies, and ice cream are all examples of ultra-processed foods.

These foods often contain high levels of ingredients like sodium, sugar, and unhealthy fats, all of which can contribute to constipation, especially if you eat them in large quantities. Some research found that a high sodium intake increased the risk of constipation in participants using two definitions of constipation: frequency and consistency. In other words, a high-sodium diet may make your stool harder to pass and cause you to have fewer stools. Foods with lots of added sugar—like chocolates, cookies, ice cream, and candy—can have the same effect. 

4. Refined carbohydrates

There are two types of carbohydrates: complex or whole carbs, and simple or refined carbs. Both eventually turn to sugar and get used for your body’s energy production, but whole carbs take longer to digest than refined carbs, so they don’t spike your blood sugar and are a healthier choice. 

Whole carbs are also less likely than refined carbs to cause constipation. A study of Korean women with constipation found that a diet based around white rice (a refined carb) was less likely to improve symptoms of constipation compared to diets based around either wheat or brown rice (both whole carbs). Additionally, a new study showed that high-quality, or complex, carbs lowered the risk of constipation by more than 30% while low-quality, or simple, carbs increased the risk by more than 80%.

5. Alcohol

The occasional beer or glass of wine probably won’t make you constipated, but several studies have linked regular consumption of alcohol to decreased bowel movements. This is partly because alcohol has a diuretic effect, causing you to urinate more and lose more fluids; fluid loss equals dehydration, which causes firmer stools that are harder to pass.

In general, the more alcohol you consume, the higher your risk of constipation. A recent study looked at the effects of daily amounts of alcohol consumption on constipation and found that the more participants drank, the more likely they were to be constipated. In this study, heavy drinkers (defined as having more than 40 grams, or around 4 standard servings of alcohol per day) were statistically far more likely to have constipation than light drinkers (defined as having up to 10 grams, or 1 standard serving of alcohol per day).

You’ll notice we included alcohol but not coffee, even though both are diuretics. That’s because coffee often has a laxative effect of its own, says Simpson, so it won’t stop MiraLax from working. It could, however, get your bowels moving a little too well, she notes, so if your stomach is sensitive to caffeine, you may want to avoid pairing coffee with MiraLax if the combination causes diarrhea or cramping.

6. Unripe bananas

If you’ve ever had a bad stomach bug or bout of food poisoning that did a number on your stomach, your healthcare provider might have told you to spend a day or two on the “BRAT” diet, an acronym for bananas, rice, applesauce, and toast. These foods are low in fiber, bland, and easy to digest, so they don’t stress your stomach while it’s trying to heal from an illness. 

As part of the “BRAT” diet, unripe bananas can help people experiencing severe diarrhea because they are high in starch and have a binding effect on stool. But that’s basically the opposite of what you’re trying to achieve if you have constipation—you don’t want to bind, you want to soften. As bananas ripen, their starch content decreases and their soluble fiber content increases, not only making them less likely to cause constipation but actually a good choice for promoting regular bowel movements. If you want to eat a banana while taking MiraLax, make sure it’s soft and ripe, with plenty of brown spots on the peel.

What should you eat while taking MiraLax?

MiraLax doesn’t need to be absorbed into your intestines to relieve constipation—it simply draws more water into your intestines, making your stool easier to pass. That means you don’t need to eat any special foods to help it work better, but there are plenty of foods you can eat to make your constipation go away even more quickly while on MiraLax.

In addition to drinking enough water, try eating:

• Foods with a high water content, like watermelon, cucumber, lettuce, and celery  
• Foods with a high fiber content, like apples, dried fruits, broccoli, beans, lentils, leafy greens, nuts, nut butters, and sweet potatoes 
• Clear soups and broths
• Whole grain foods, like oats, popcorn, and brown rice 

Gastrointestinal side effects of MiraLax

Simpson says most people don’t have stomach problems while taking MiraLax, but it can sometimes cause gas, bloating, or cramping, especially if you take too much too soon. Follow the dosing instructions on the package and be patient. When you take your dose of MiraLax, drink plenty of water to maintain adequate hydration—it will help minimize common side effects. It usually takes about one to three days to work, so don’t rush to take more if nothing happens immediately.

Many of the foods that cause constipation—like fatty, fried, and sugary foods—can also make the side effects of MiraLax feel worse. “When your gut’s already a little sensitive from a laxative, heavy meals can add to the discomfort; lighter, easier-to-digest foods are usually a better match while MiraLax is doing its thing,” Simpson says.

Although most people tolerate MiraLax without any issues, there are times when you may need to contact a healthcare professional for medical advice while taking it. According to David DiCaprio, DO, gastroenterologist and internist with Summit Health, if you experience excessive diarrhea with signs of dehydration, like lightheadedness or fainting, you should check in with your medical provider. He also recommends contacting a provider if you take MiraLax and don’t have a bowel movement in the expected timeframe, or experience extreme gas and a swollen stomach. These could be signs of a bowel obstruction.  

Tips for maximizing MiraLax benefits

MiraLax is gentle enough to be used at any time of day or night, with or without food, but there are some ways you can use it so it works more quickly and effectively. 

Dr. DiCaprio offers the following tips for making the most of MiraLax’s benefits:

• Your bowels are most active during the day, so take it first thing in the morning. 
• Eat a light meal after taking it; eating activates your metabolism, which can help MiraLax work better.
• Drink four to eight ounces of water with your MiraLax dose, and make sure to stay hydrated throughout the rest of the day, too.
• Get some exercise; it stimulates your bowel muscles and keeps stool moving through your intestines.
• Take a fiber supplement if you can’t get enough high-fiber foods in your diet to keep stools soft after the MiraLax dose stops working.